Method for eliminating foaming in the recovery of sulfuric acid from an olefin recovery operation



Patented Aug; 19, 1947 METHODZFOR unmarried-m NG IN THE nacovcmzor SULFURIG A moM AN OLEFIN RECOVERY UPERATIQN John H;" Cone, Goose Creek, Tex, :i.

Standard Oil Development. Comm; 1 notation of Delaware Application June 4, 1945; Serial No. 597,404

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The present invention is directed to a method other portions of the system in order-to elimifor concentrating relatively .we'aki-fsulfuric acid nate or prevent-foamingin the system. which previously has been employed for treat The treatment of'a cr'ude petroleum or a pcing hydrocarbons. v Y troleum fraction with a selective solvent to sep- More particularly, the present invention i di-" 5 arate it into a more unsaturated component rected'to a process comprisin the tre'atmentof and "a more. saturatedcbmponent is well known lowv molecular vweight' hydrocarbons-including "to'the 'artgns exa ples of we n w se e olefins with sulfuric acid to form an extract, tive soli'ien t' suita le I 1; this p 'm the-recoyery of absorbed and rcacted-hydrocarnientionedghenbl sulfur "dioxide; furfuraland bons from the extract and the ne ntrafiefib BB fdichlorcithyl ether. As the selective solthe recovered acid, wherein}unsaturated cyclic ventiriroces'gis conventionallypracticed, the mah dr sar ns .are employed Itoprevent .foaming te'rial inseiiible "in g the solvent and separat d of thejextractand of the sulfuri acid-undergothereiroln'f jgrav'ity settling is designated as me concentration, a; the rafiinjat'e; iraction while the materiatdis It is conventional ,to. the art to r eco veralq'w so1vedjin-- the, selective solvent is designated-as molecular. weight olefins from'a hydroca b the extractfiraction. In: accordance with the mixture by contacting the mixture with-65% u1- present i'r'i ntionfit has been found desirable to furic acid. As an example'of a typical. op raemploy as t iiti icrud'e' petroleum or petroleum tion, a hydrocarbonfeed stock including normal fractiofiemplpyd as feed stbck in the solvent butane, isobutylene and normal butylene may b "extraction step a sc -called naphthenie base oil.

brought into contact with sulfuric acid 1m Such etroleum are, commonly obtained from actionizone under a pressure substantially-1n the Gulfco'ast "areaof "the United States" and excess of. atmospheric in ordertp. form an\ex contain substantial amountsoi' naphthe'nic contract. 'Ihe extract is sent. to a vent drum where t 017 em en a m e its pressure is reduced to=substantiall3 atmos- 9 flien a n e m constituents- Dheric-with the resultant .releaseofa-the butanes 5 a Fii lt xsmp eorya material obtained andbutylenes, andthe remainder-48mm Sent to by extracting a petroleum traction including a. regenerator where polymers alcohols and ole; substantial amounts of cyclic hydrocarbons with fins resulting from the reaction of the sulfuric 5 solvent may be mentiorfed a m" acid w t th hydrocarbon mixture are separat carbon extract obtained by contacting a Coastal ed as overhead fractions and the acid is regendlstmate.fract1n with such a fraction erated and an acid of 45% strength recovered. commercially designated at 75'phem1 extract The acid is removed from the regenerator to an f-ouowing physical characteristics;

acid concentrator where its strength'is increased to 65% and is then returned to the reactionzone 0 TABLE I of the system. In conventional operation a f 'g 5 u antial foamingis encountere i t e vent a? gi g'i'' 'fi um, the regeneratorand in the acid concenatzmoFs '7 so zgat ria d thisfffoaming reduces the capacit f 40 2 5 91 g O sU 39 ese por ions 0 he system, Y In accordance with the presentinvention foam Distillation at 10 Pressure ing in the vent drum, regenerate! and acid con- IBP 'F centrator is'eliminated by adding to the'sulfuric' acid being circulated in the system a small The I-phenol extract was obtained by extractinga light lubricating-oil fraction separated from 9, Gulf Coast crude petroleum. The light lubricating oil fraction had the following character- 'isticsr Tears II Gravity API 25.8 Flash 00, F'. 32o Viscosity at 100 F. SSU 82 Viscosity at 210 F. SSU 372 Pour (ASTM) F. -35

It will be understood that the amount of the constituent separated from a crude/petroleumor petroleum fraction by contacting the fraction with the selective solvent which is used for suppressing the foaming may be varied over a-substantial range when used in a sulfuric acid-hydrocarbon mixture. Under extreme conditions it-maybe desirable to employ as much as 2 gallons of the extract per 20,000 pounds of sulfuricfacid hydrocarbon mixture while under other conditions 1; pint of extract per- 20,000 pounds of the sulfuric acid; hydrocarbon mixture may be found adequate. Under normal operating conditions the 75-phenolcextract having the characteristics'given above has been found to produce satisfactory resultsfin a solution including 65% -suliuric"acid and isobutylene when used in amounts in the proportion of 1 quarto'f the- IS-phenol extractper 20,000 pounds of the sulfuric acidisobutyl'e'ne 7 solution. It is also to be understood that a nuzn ber of petroleum fractions are satisfactory as a 1 charge stock from which the constituents soluble in a selective solvent may be obtained. For'ex I ample, middle distillates, heavier'lubricatlng" fracl-j-- tions and fractions extending fromfthe gasoline boning range to asphalts may be bpbught. nt contact-with a selective solvent --for-the" recoverytherefrom of constituents which will be suitable for suppressing foam mixtures.

., The invention will now be describied iin- -greater I being designated'by At-ftheu acid-regeneratingzone by B and the acid concentrating *zone' by C. The reaction zone A includes a first"stage.{reactor H, a first stage settling drum i2, ajs'fecond stage reactor l3 and a second stage sewing-ar s H. The acid regenerating zone-.Bfijncludesven drum l5 and regenerator-vess'el Hi. The 'acidc'o centrator zone C includes an acidconcentratorJ- shown as a single vessel l7 and arr-accumulator;

so" in sulfuric acid-hydrocarbon In order to prevent foaming of the acid in vent drum I 5, regenerator i6 and acid concentrator H, constituents obtained as an extract fraction when contacting a selective solvent with a petroleum fraction comprising a substantial amount of cyclic hydrocarbons is added .to the circulating stream of acid. In the drawing the means for adding the constituents derived from petroleum is indicated as inlet I 9 and for convenience this material is designated in the drawing by the legend cyclic petroleum constituents" although'lt will be understood that these constituents may include other materials in additionto cyclic materials which are dissolved, in the selective. solvent when it is brought into contact with the crude petroleum or petroleum fraction.

'The hydrocarbon feed stock is passed from vessel is byline 20 in which is arrangedgapump split, with a portionpassingthrough-line 26f to first stage" ettling Zone 12 and. the'jremainder being recycledto line 20' via'line, 21. Toflthe extract'ilowing through line ii is added-extract withdrawn through line 28 from the second stase settling zone l4.- The extract withdrawn from drum l4 and theiextract withdrawn from the first stage" escu r are mixed in line as and the J mixture-o'f-extract is then. discharged into the hy-- drocarbon stream. in line 20. Thehydrjocarbon apo s in reactor vessel H' which" are not absorbed'or do not react with sulfuric acid therein .are"removed' asi overhead through line" 29 and discharged; into the upper portion .of settling drumfl l. The unabsorbed'hydrocarbons pass from settling drum i2 through line '30, containing heat exchanger 3|, and discharge through line 32-"and- 33 -in the second stage're'ac'tor 1313* Ex i ,tract-rrornthe-lower portion of second stage. a reactor -l3-is withdrawn through line 34 and-the 4 streanis'blit, with a portion passing .through line 35 to second stage'settllng zone l4 and the remainderi passing through pump 36 anddischarging-into the hydrocarbon stream passing through line 30. The regenerated and reconcentrated sulfuric acid is added to the stream flowingin line 34 by line 31.

Unabsorbed and unreacted hydrocarbon vapors from the-second'stage reactor I3 pass through v line 38 to second stage settling vessel l4 and the unreacted and unabsorbed hydrocarbons from vessel l4 are withdrawn from outlet 39.

' Settling drum I2 is operated under superatmospheric pressure and to recover hydrocarbons from the extract, it is desirable first to release the pressure from the. extract and subsequently subject it to a heating operation. In the drawing,

the extract from settling vessel I2 is withdrawn vessel 65. The feed hydrocarbons are passed to" the system from storage vessel 18].

In the reaction or absorption zone. hydrocarbons flow through the first and'second stages in sequence and the sulfuric acid is passed into the second stage to form an extract therein,

the extract is taken from the second stageto.

the'first stage where it is enriched and the resultregeneration and acid concentration zones. The

A the feed through outlet 48, cooler. and discharge into:

vent drum I5 is arranged between settling vessel through line 40 to vent drum [5 where the presaccumulator 50. Uncondensed constituents are removed in gaseous form from accumulator through outlet 51 while condensate is removed through outlet 52 containing pump '53. After inlet, line 08',to, the stream process, i n-the drawing, the

240 F. and a top the condensate passes through pump 53, the stream is split and a first portion is passed through line 54 and discharged as a scrubbing medium in scrubber 46. a second portion is passed through line 55 and again divided with one portion discharging through line 56 into regenerator l6 and the remaining portion passing through line 5'1 and heater 58 and discharging into regenerator [6. A portion of the stream in line 52 is withdrawn through line 60 and mingled in line 59 with the bottoms withdrawn from scrubber 46. The mixture in line 59 includes alcohol and polymer and i withdrawn from the system to a suitable arrangement, not shown, for recovering these materials.

The acid is withdrawn from the bottom of regenerator tower l6 through line 44 and passes to acid concentrator [1. In this vessel the acid is heated by steam passing through coil 62 and water vapor is driven from the acid and discharged through outlet 63. The acid from vessel I1 is discharged into an accumulator vessel 65 containing a cooling coil 66 and vent 61. From vessel 65 the-regenerated acid is passed through lines 31 and 34 to -the hydrocarbon stream in line 30. In order to replace acid lost in the operation, make-up acid may be introduced through of regenerated acid. 1 As an example illustrating v feed stock withdrawn from vessel illiniayconsist of butane, 32%" normal butylene and 18% isobutylene. The first stage'r'eactor vesselmay be operated at a temperature of '100" F. and a pressure of approximately 40 pounds per square inch while second stage reactor-'13 may be operated at a temperature of 70 F. and und'r a pressure of 135 pounds per square inch; j Under these conditions, the pressure in first stage settling zone i2 is approximately 135 pounds per square inch; the pressure is released to atmospheric as the extract is passed into vent drum l5.- TheIegenerator-IB may be operated with abottom temperature of temperature of 160 F. with acid of a concentration of approximately 45% withdrawn therefrom through line 44. The acid may be concentrated in unit, IT to a strength of. ap proximately 65%.

A plant having the reactor'zone, regencrator zone and acidconcentrator zone designed to operate under the temperature and pressure conditions given above was designed to regenerate and concentrate 20,000 pounds of sulfuric acid-hydro carbon extract per hour. Prior to the addition of the unsaturated hydrocarbon material exthe operation of the 50% iso and normal a g acid with the water vapors in the acid concentrator unit.

Having fully described and illustrated the. present invention, what I desire to claim is:

1. In the treatment of an extract resulting from the contact of sulfuric acid with low molecularweight olefins, the steps of incorporating in the extract unsaturated cyclic hydrocarbons obtained by bringing a petroleum fraction including said unsaturated cyclic hydrocarbons into contact with a selective solvent capable of dissolving said cyclic hydrocarbons from said petroleum fraction, said cyclichydrocarbons being added in an amount sufficient to eliminate foaming in the ex-. tract upon heating under a reduced pressure and subsequently heating the extract under a reduced pressure to recover oleflns therefrom.

2. A method in accordance with claim 1 in which the fraction is added to the extract in the proportion of approximately one quart per 20,000 ounds of extract.

3. In a method involving the steps of contacting a predominantly C4 hydrocarbon feed stock comprising olefins with sulfuric acid under superatmospheric pressure in a reaction zone to form an extract, removing the extract fromthe reaction zone to a regeneration zone, heating. the 1 extract and reducing the pressure imposed thereon in the reaction zone to separate it into a hydrocarbonjracticn and an acid fraction and recycling ofthe recovered sulfuric acid to the reaction zone. the step of adding to the circulating sulfuric acid stream unsaturated cyclic hydrocarbons obtained'by bringing a petroleum fraction containing cyclic hydrocarbons into contact with a selective solvent capable of dissolving said cyclic hydr carbons from said petroleumfraction,

. said cyclic' i iydrocarbons being added in fan tracted from a crude petroleum or petr0leum fraction in accordance with the present invention, severe foaming was experienced in the vent drum. acid regenerator and acid concentrator to such an extent that these units could be operated only at approximately one-half the design capacity. Upon the addition of an extract obtained from petroleum oil to the sulfuric acid-hydrocarbon mixture being charged to vent drum [5, the foaming was eliminated and the output of these units increased to the design capacity. Under normal operations, one quart per hour of an extract derived from petroleum added to the stream of sulfuric acid-hydrocarbon charged to the vent drum satisfactorily reduces foaming. The acid concentrator I1 is separated into four compartments in the plant described aboveand the acid withdrawn from the last compartment appears to be free from oil even upon settling; this indicates amount substantially to eliminate foam in the regeneration alone. i

4. A method'in accordance: with claim 3 'in which said constituents are added to the circulat ing sulfuricigcid stream in an amount of the order of one quart to 20,000 pounds of sulfuric acid extract passed to the regeneration zone.

5. In a method including the steps of contacting a hydrocarbon stream comprising a substantial portion of C4 hydrocarbons and appreciable amounts of olefin with sulfuric acid in a reaction zone under conditions to form an extract, separating the resulting extract in an acid regeneration zone into a hydrocarbon fraction and an acid fraction of approximately the same concentration as that in the reaction zone, the step of adding to the extract being sent from the reaction zone to the regeneration zone unsaturated cyclic materials derived from petroleum containing them by extraction of said petroleum with a selective solvent for said cyclic materials, said cyclic materials being added in an amount sufficient to prevent foaming in said regeneration zone.

6. A method in accordance with claim 5 in which the constituents are present in an amount of the order of 1 quart per 20,000 pounds of extract passed to the regeneration zone.

7. A method in accordance with claim 5 in which the constituents are obtained by contacting a distillate derived from a naphthenic base crude oil in the lubricating oil viscosity range with a selective solvent.

8. A method in accordance with claim 5 ir which the constituents are obtained by contacting a distillate fraction having a viscosity in th lubricating oil range and derived from a naphthenic petroleum by dissolving them in a selectiv' 8 solvent and in whichapproximately 1 quart of the constituents are added to 20,000 pounds of the UNITED STATES PATENTS sulfuric acid extract. N ber Name Date JOHN CONE. 2,3 4, 80 Read -Bec. 8, 1942 0 5 2,330,077- ODell Sept. 21, 1943 REFERENCES CITED 1,964,641 Mathias June 26, 1934 1,775,622 Heckel et a1 Sept. 9, 1930 The followmg references are of record 1n the 1 919 664 Merrill et a1 July 25 1933 file of this patent:

1, 174,933 Humphreys et a1. Nov. 20, 1923 

